Patients with frontal lobe damage have difficulty remembering the source or context in which information was previously learned, yet their memory for content information is relatively unimpaired. The proposed experiments provide a comprehensive analysis of the effects of frontal lobe damage on memory for source information. Specifically, the research program will 1) identify the degree of a source memory deficit in patients with frontal lobe lesions; 2) propose a new multinomiaI model of source memory; and 3) analyze implicit expressions of source information. Comparing the results from the direct and indirect tests will be very important for determining if frontal lobe patients' source memory deficit is due to the absence of this information, or if this memory deficit is due to the inaccessibility of this memorial information on tests requiring deliberate recollection (i.e., direct tests). In addition, the present project introduces an important technique for assessing source memory that emphasizes the fact that subjects can recollect a variety of information about the source of an earlier studied item. The proposed studies should help characterize the severity of the source memory deficit in frontal lobe patients, and they should also contribute to our understanding of the more general issue of source memory.